Copyright Malcolm Faed.
Images and text may only be copied with the permission of the author.
This blog includes personal things of interest including electric vehicle conversion. I have documented the conversion of a petrol (gas) powered vehicle to Electric. http://www.austinev.org/evalbum/1149.
The blog now documents the conversion of a BMW E30 to electric.

Wednesday, 18 February 2009

I am happy(er) with open loop speed control now. After many hours diving up and down our short driveway, and logging 10kms! I found that the throttle response was too precise.

After a lot of fiddling I lowered the switching frequency to 4.5kHz because I was curious about audible noise at a lower switching frequency. As a result, the throttle response is much less aggressive. Makes sense after you think about it for a minute.

I have also been able to decrease the acceleration ramp time without the 'bunny hopping'.

The bad news.

Closed loop and Torque open loop have been non starters. Perhaps you need many more that 40 pulses per revolution for closed loop to be useful. I still have a service call in with Danfoss as I would like to have the other control modes available.

Regardless the 40 pulse per revolution input is nicely scaled and outputs a programmable frequency that is proportional to speed to drive the speedo.

The rear springs were struggling a bit under the load so I have installed air bags . The reason I chose air bags over new springs to level the ute is because when I upgrade to lighter batteries in the future I would like to level it again.